Electrical switch having deformable contact members



p 1966 R. MGGIRR ETAL ELECTRICAL SWITCH HAVING DEFORMABLE CONTACT MEMBERS Filed Oct. 8, 1962 m m m m d FIG.|

INVENTORS ROBERT MGIRR BENJAMlN A. GAY

QAAR fl mUik United States Patent ELECTRICAL SWITCH HAVING DEFORMABLE CONTACT MEMBERS Robert McGirr, Orwigsburg, and Benjamin A. Gay, Tamaqua, Pa., assignors to Atlas Chemical Industries, Inc., Wilmington, Del., a corporation of Delaware Filed Oct. 8, 1962, Ser. No. 228,923 2 Claims. (Cl. 200-142) The present invention relates to an improved electrical switch and more particularly to an electrical switch which disconnects electrical contacts. The switches of the present invention are especially suited to be actuated by an explosive charge.

Some types of projectiles and missiles require reliable, compact electrical switches which are stable to large multidirectional forces and which are operable while exposed to such forces, for example, when the projectile or missile containing the switches are in a state of violent tumbling or rolling.

The present invention provides an electrical switch that operates in a positive manner to break an electrical connection by disconnecting one electrical contact from another and is independent of the position of the switch or forces acting upon the switch.

In general, the switches of the present invention comprise a wedge member moveable along a line and a pair of contacting electrode members spaced from said wedge member. Preferably the contacting electrode members meet at a soldered juncture. The wedge member has a nonconducting striking surface. At least a portion of one of the pair of electrode members is positioned across the line of travel of the wedge member. The electrode portion positioned across the line of travel of the wedge member is comprised of a metal deformable into a permanent set. The wedge member is moveable from a first position wherein it is out of contact with the electrode portion positioned across the line of travel of the wedge member to a second position wherein the wedge member contacts the electrode portion positioned across the line of travel of the wedge member and deforms the portion into a permanent set permanently separating the electrode members by Wedging the nonconducting striking surface of the wedge member between the electrode members. A driving means is included to drive the wedge member from the first position to the second position.

The latter mentioned driving means may comprise a compressed spring released by either a mechanical or electrically actuated release mechanism. However, it preferably comprises an explosive charge fired by electrical energy. A particularly suitable driving means is an electrically actuated squib.

The present switch provides a positive circuit breaking means without involving complicated or cumbersome mechanical arrangements. After the breaking action has been completed the present switch contains no loose or moveable metallic elements which could cause an undesired short circuit. The wedge action of the present switch initially deforming one of the switch electrodes precludes befouling and consequent shorting of the switch by metallic residue on the switch elements.

The invention will be better understood from the following description when considered in connection with the accompanying drawings.

FIGURE 1 is a longitudinal cross-sectional view of a switch in accord with the present invention showing the wedge member in the first position.

FIGURE 2 is a longitudinal cross-sectional view of the switch of FIGURE 1 showing the wedge member in the second position.

In each of the views like components bear like numbers.

A generally cylindrical metallic outer shell member 11 is sealed on one end by a plug of nonconducting material 13 and on the other end by a second plug of nonconducting material 15. The plug members may suitably be fabricated of such nonconducting material, as plastic, asphalt, rubber or glass. Preferably, the plug members are fabricated of a ceramic material. A wedge member 10, moveable along a line, is positioned within shell 11. Wedge member 10 has a nonconducting striking surface 12. Nonconducting striking surface 12 or suitably the entire wedge member 10 may be fabricated of a nonconducting material, for example, resin, bard rubber, compacted fiber board, or ceramic material. A pair of electrode members 17 and 17 enter shell 11 through plug 13 and terminate within the shell. A portion 14 of electrode member 17 is positioned across the path of travel of wedge member 12 and contacts electrode member 17 along juncture 16. Portion 14 is fabricated of a metal deformable into a permanent set, for example, copper or nickel-iron alloy. Suitably electrode members 17 and 17 may be entirely fabricated of a metal deformable into a permanent set. Juncture 16, common to electrode members 17 and 17', is preferably soldered with a soft solder, such as an indium-silver alloy, to insure a low resistance circuit prior to operation of the switch and to minimize the force required to break the junction.

The portions of electrode members 17 and 17 within shell 11 are encircled with an insulating collar 18 positioned about the inside of shell 11. Insulating collar 18 may suitably be fabricated of heavy paper or plastic.

Wedge member 10 is driven toward plug 13 by a gasform-ing explosive charge 16, suitably composed of lead mononitroresorcinate, positioned in proximity to wedge member 10. A firing means comprising leg wires 19 and 19 enters shell 11 through plug 15 and is electrically connected to a high resistance bridge wire 20 embedded in charge 16.

FIGURE 2 shows the device of FIGURE 1, after firing of charge 16. Wedge member 10 has been moved into a permanent wedged position between separated contacts 17 and 17'. The gas-forming explosive charge 16 (shown in FIGURE 1) may be fired by applying sufficient electrical energy via leg wires 19 and 19' to heat bridge wire 20 and fire the charge. Wedge member 10 is driven by the force of expanding gases in chamber 21 toward plug 13 and is wedged between separated electrode members 17 and 17'. Portion 12 of electrode 17, fabricated of a metal deformable into a permanent set is permanently deformed by wedge member 10 into a position out of contact with electrode member 17'.

It is obvious that modifications and alterations of the present invention will occur to one skilled in the art, and it is understood that changes can be made with-in the scope of the appended claims.

What is claimed is:

1. A normally closed switch comprising an outer shell,

a symmetrical pointed wedge member the sides of which converge to an apex and moveable along a line positioned Within said shell,

a pair of contacting electrode members positioned and permanently secured within said shell,

at least a portion of one electrode member of said pair bent back on itself and positioned across the path of travel of the point of said wedge member and so slanted with respect to the path of travel of said wedge member as to be pried away from the other electrode member upon movement of said wedge,

said portion composed of a metal deformable into a permanent set,

3 4 said wedge member moveable 2. The switch of claim 1 wherein the pair of contactfr-om a first position wherein the wedge member is not ing electrode members meet at a soldered juncture.

disruptive of contact between said electrodes to a second position wherein the wedge member con- References Clted by the Exammer tacts said portion and deforms said portion into a 5 UNITED STATES PATENTS permanent set and permanently separates said elec- 2,511,955 6/1950 West 53 trade members by wedging the nonconducting strik- 2,931,874 4/1960 Leaman ing surface of said wedge therebetween, and 3 003 045 10 19 1 Tichenor 1 g electrically actuated squib means to drive said wedge member from said first position to said second po 10 BERNARD GILHEANY Primary Emmmer' sition. H. B. GILSON, Assistant Examiner. 

1. A NORMALLY CLOSED SWITCH COMPRISING AN OUTER SHELL, A SYMMETRICAL POINTED WEDGE MEMBER THE SIDES OF WHICH CONVERGE TO AN APEX AND MOVABLE ALONG A LINE POSITIONED WITHIN SAID SHELL, A PAIR OF CONTACTING ELECTRODE MEMBERS POSITIONED AND PERMANENTLY SECURED WITHIN SAID SHELL, AT LEAST A PORTION OF ONE ELECTRODE MEMBER OF SAID PAIR BENT BACK ON ITSELF AND POSITIONED ACROSS THE PATH OF TRAVEL OF THE POINT OF SAID WEDGE MEMBER AND SO SLANTED WITH RESPECT TO THE PATH OF TRAVEL OF SAID WEDGE MEMBER AS TO BE PRIED AWAY FROM THE OTHER ELECTRODE, MEMBER UPON MOVEMENT OF SAID WEDGE, SAID PORTION COMPOSED OF A METAL DEFORMABLE INTO A PERMANENT SET, SAID WEDGE MEMBER MOVEABLE FROM A FIRST POSITION WHEREIN THE WEDGE MEMBER IS NOT DISRUPTIVE OF CONTACT BETWEEN SAID ELECTRODES TO A SECOND POSITION WHEREIN THE WEDGE MEMBER CONTACTS SAID PORTION AND DEFORMS SAID PORTION INTO A PERMANENT SET AND PERMANENTLY SEPARATES SAID ELECTRODE MEMBERS BY WEDGING THE NONCONDUCTING STRIKING SURFACE OF SAID WEDGE THEREBETWEEN, AND ELECTRICALLY ACTUATED SQUIB MEANS TO DRIVE SAID WEDGE MEMBER FROM SAID FIRST POSITION TO SAID SECOND POSITION. 